This invention relates generally to apparatus and processes for compressing moisture containing material and more particularly to apparatus and processes for reducing the moisture content of moisture containing material such as wood or woody biomass, e.g. wood chips or green wood chips, pulp chips, hogged wood, sawdust, woodflour, wood bark, wood fiber pulp, lignin, and the like; vegetable/fruit biomass, e.g. cornstalks, peat, and the like; animal/fowl biomass, e.g. manure and the like; paper mill sludge; industrial mill sludge; municipal sewage sludge; coal slurry and the like; and for enhancing the production of ethanol and methanol.
As is known to those skilled in the moisture removal or reduction art, the removal or reduction of moisture from the foregoing examples is done for a variety of purposes. For example, moisture is removed from wood or woody biomass to convert the biomass to fuel, to enhance a pulping or paper making process, to produce fertilizer from animal/fowl biomass, and to reduce the moisture content of certain wood biomass, such as wood bark or other residue from a pulping or paper making process, prior to the typical burning of such residue for riddance as such residue is known to unwantedly rapidly accumulate in large quantities.
Due to the constant dwindling of the world's known oil reserves, it is highly desirable to be able to use wood, vegetable/fruit and animal/fowl biomasses as substitutes for oil and as an energy saving fuel source, such as boiler fuel. This is due primarily to their cheapness of cost and plentiful availability. However, as is known to those skilled in the art, and with regard to wood biomass as an example, the primary deterrent to the use of wood chips or green wood chips and the like for an energy saving fuel source, such as a boiler fuel, is the naturally high moisture content of the wood chips. Generally, the moisture content is so high that the wood chips cannot be burned efficiently as boiler fuel but first must be pre-dried. Such pre-drying unwantedly consumes energy and in most instances the amount of energy consumed in pre-drying virtually renders the use of wood chips as a fuel saving energy source a self-contradiction.
By way of further example, the two basic methods known for reducing moisture in wood biomass, e.g. wood chips for fuel such as boiler fuel, are: (i) heat energy to vaporize the moisture, (ii) mechanical energy to squeeze the moisture out. A variety of mechanical apparatus and methods of dewatering of wood chips, pulping rejects and bark are known to the art such as bark presses, roll presses, jaw presses and screw presses. These apparatus have not been highly successful in removing or reducing the moisture content of wood chips, particularly the bound water, i.e. the water held by physical/chemical bonding within the cell wall or cellular structure of wood biomass. It has been stated by John G. Haygreen, in his article entitled, "Potential for Compression Drying of Green Wood Chip Fuel," FOREST PRODUCTS JOURNAL, Vol. 31, No. 8, August 1981, "It should not be expected to lower the moisture content of wood below 30% by mechanical means." As is further known to those skilled in the art, the use of wood chips as an economically feasible source of boiler fuel generally requires that the moisture content of the wood chips be reduced below 30%.
Accordingly, there exists a great need in the art for apparatus and processes for reducing the moisture content of moisture containing materials such as the above-noted wood, vegetable and animal biomasses below that which may be achieved by presently known methods and apparatus for moisture removal or reduction, and a great need in the art for apparatus and process for enhancing the production of ethanol and methanol.
Further, this invention relates generally to apparatus and processes for biodigesting, decomposing, or composting organic material, such as for example animal biomass, e.g. manure, cow manure, and the like. As is known to those skilled in the art, animal biomass, such as cow manure and the like, decomposes naturally and it is advantageous to facilitate or accelerate such decomposition for use as organic fertilizer or soil conditioner. While many biodigesting, composting, or decomposing apparatus and processes are known to the art, because all such prior art apparatus and processes have various deficiencies of operation or attendant unwanted expensiveness of operation, they have been found to be not as useful as the processes and apparatus of the present invention for biodigestion. Accordingly, there is a need in the art for improved processes and apparatus for the biodigestion, decomposition, or composting of organic materials such as animal biomass, e.g. cow manure and the like, and further, if desired or required, for apparatus and process for reducing the moisture content of such decomposed or composted organic material, e.g. cow manure and the like, to further enhance its use as an organic fertilizer or organic soil conditioner or to further enhance its ease of transportation and use through reduced moisture content.